In a proper setup your elbows are pointing to the respective hip-joints at address. For solid shots it's imperative to maintain the relationship between them from address to the early part of the follow-through. This is particularly true of golfers who set up in an upright posture.
To keep the relationship between your elbows and hip joints constant throughout the swing, you need to make a point of turning your hips fully on the backswing so your right elbow is pointing at your right hip at the top. That facilitates the correct positioning of your right elbow at impact and encourages square clubface alignment.
Failure to turn your hips enough causes your right elbow to move behind your right hip and stay too far from the side of your chest at the top. That hampers bringing your right elbow back down to the side of your body through the ball.
When that happens, your upper body cannot work in concert with your lower body on the forward swing. To position your right elbow properly at impact due compensation is called for at the early stage of the forward swing, which is hard to repeat on a consistent basis. Every compensation in your golf swing costs you accuracy and consistency.
To rotate your hips properly and to keep the relationship between your elbows and hip joints constant, you need to be sure most of your bodyweight moves backward to the outside of your right heel at the top of the backswing with only a very small amount of weight shifting forward to the inside of the toe of your left foot. Your left foot is almost floating.
You will feel as if you were twisting the spikes out of the ground with your right foot, your left knee pointing to a spot behind the ball. This is a must for players who set up in an upright posture.
Of equal importance is to position your hands between your right ear and shoulder at the top unless you set up in a bent posture. That augments proper shoulder rotation behind the ball, allowing your right elbow to correctly point at your right hip in the backswing.
Once you've arrived at the correct position at the top, all you have to do to hit the ball firmly is transfer your bodyweight to the left on the downswing by sliding your hips or moving your left knee toward the target. Your right elbow is already pointing at your right hip joint and you don't have to worry about bringing your right elbow back down to the side to create a powerful impact position.
Positioning your right elbow correctly through impact so it is pointing to the right hip joint facilitates striking the ball just before the clubbed reaches the lowest point of its arc. You will naturally hit the ball first and then the turf as your swing center moves forward when you shift your bodyweight to the left at the beginning of the downswing.
Incidentally, for the correct swing plane and path golfers who stand over the ball in a bent posture need to place their hands below their right shoulder, allowing their right elbow to lag behind the seam of the shirts or point behind at the top of the backswing so their left arm crosses their chest.