At 47, you have to consider that you're on the "downslope" of mucle development. Consider that you have difficulties like slower recovery and decreasing testosterone level. I mention this because it's important to be realistic about what you can do with your body, and what to expect in the future.
I work out with guys that are in their 40's and 50's at the gym, and most of them have evolved into a "maintenance" regimen where they are working towards overall fitness and health, and they don't sling heavy weight any more. The only late 40's or older guys who are legitimately large and throwing around heavy weights are guys who have been doing it for a decade or more already.
I'm not saying that larger arms aren't possible, because they most certainly are. Getting up to 19" arms at your age is highly irregular and very difficult given that you don't currently have a solid base of muscle established. Frankly, the only way you're going to be guaranteed to get that big at this point is with test boosters/supplementation (aka, steroids). The reason why I say this is because 19" arms that are actually comprised of muscle are extremely difficult. You'll realistically see less than 5% of all weight lifters and body builders develop arms that big or larger. If you do it naturally with OTC supplements, you will likely need at least 10 years of solid lifting to get your arms up that large, and that's supposing that you have a mesomorphic or endomorphic body composition that supports large scale muscle development. Some people-generally ectomorphs-will never be able to naturally get arms that big.
The best way to look overall "big" is to build up the shoulders; especially the lateral and anterior deltoids. The best way for your arms to look big is actually through the triceps for most people.
With all that being said, there are a couple of solid strategies for putting size on your arms. The two leading methodologies are Lift Short and Heavy, and Muscle Breakdown/Super Set/Shock Set lifting. Ultimately what it comes down to is a combination of isolation lifts, compound lifts, and occasional muscle confusion or shocking. You do need to separate muscle groups accordingly with your workouts, and dedicate sufficient time to each muscle group when working out.
I work out my arms on Day 2 of my rotation, and it consists of biceps and triceps. I start with heavy gross motor movements with heavy seated dumbbell curls or preacher bench barbell curls. I fully extend my arms to get the full range of movement and stretch in the mucle tissue. This works quite well. At least 75% of people in the weightroom at my gym have horseshit form and don't utilize the full range of motion because it makes it harder for them to lift heavy and feed their egos. The goal should be to do as heavy as possible weight while still maintaining proper form. Now, there are reasons to do limited range of movement/stalls like when doing 21s, but there are people who do nothing but stalls/LROM and get frustrated becauase their arms have limited growth.
As I progress through my workout, I move from gross movements to isolated movements to concentration isolation movements (very low weight).
For Triceps it's the same concept going from gross to fine movements.
Sample USACS arm day:
preacher bench barbell curls: 8-10reps for 3 sets (weight is heavy enough so you can't do any more beyond 10reps)
preacher bench close-grip barbell curls: 8-10reps for 3 sets
Standing barbell curls: max weight to do 8-10 reps, 5sec pause, superset dropsets after each heavy set using barbell at ~60% weight of heavy set
Alternating arm cable curls: 8-12reps for 3 sets
Incline Bench alternating arm dumbbell curls: 6 reps right arm, 6 reps left arm, 3 right, 3 left = 1 set. Do 3 sets.
Hanging bicep isolation curls (a favorite of Arnold's): 4 sets of 8-10reps
Supine overead tricep pull & press (aka Rich Gaspari triple-head tricep pull and press) with plate loaded preacher bar: 8-12reps for 3-4sets
Cable T-bar tricep extensions: 8-12 reps for 3-4 sets
reverse grip t-bar tricep extensions: same^
Single hand reverse grip cable extension: 8-12 reps per arm for 3 sets
Tricep cable extensions with 2-handed rope: same^
Bar dips: 10-16 reps for 3-5 sets (depending on energy)
As the workout progresses, I drop the weight down and concentrate on form and isolation.