There are some great opinions whether or not to fix the elbow, however, I would personally take a look at the image in directions before making an ultimate decision.
First, make a new post and get peoples opinion on the overall image compisition. Don't mention the elbow in the new post, nor say - "would you change anything?" It was really hard to look at the image, knowing you thought there was a problem with the elbow. Still in the first direction, ask the model what she thinks of it, ask her what if anything would she do different in it was shot over again.
Second, fix it, then post for opinions, and again don't mention the elbow, its really hard for any one to be critical if they are already given something to be critical about. This time, ask if there is something that could be changed. Still in the second, ask the model her opinion of this one, on a different day if possible, and act like this is is different, but don't tell her that you fixed anything.
Overall, now I would personally fix it before submission, but I really cannot comment if I would have in the begining. The body has imperfections, not everyone has a "Photoshop Cover Model Body." Do not exploit imperfections as they will continue to haunt you if you let them.
Photographer in Training