I would say lock your elbow.
If your elbow isn't fully locked out, you're not maintaining bone on bone pressure & tire out quickly. Your alignment will suffer as a result.
You can rotate your shoulder to move your forearm out of the way. As you hold your bow-arm out, where is the inside of your elbow pointing? If you draw a line through your elbow joint, would bet that the inside is pointing to around 1 o'clock. If you rotate your shoulder, you can keep your hand in the same vertical or canted positon (canting alows for further rotation) & move your insside elbow position to 3 o'clock. This will then move your forearm out of the way.
Here's an exercise; Close your eyes & hold your bow arm out, as though you were shooting. Now bend your elbow until your hand touches your head or face. Where did it touch?
When I used to coach beginners & kids, 90% of them would bring there hand to the top of their heads.
What you're after is to get your fingers to touch your lips or nose.
If you
start the excercise with your bow hand on your lips & then
extend your elbow out
without moving your shoulder you will end up with your arm fully extended, elbow locked & your shoulder rotated correctly, so that your forearm is out of the path of the string.