One thing they look at is whether the fist was clenched; it's hard to elbow someone with an unclenched fist. Flailing arm is different, but for the proper nasty elbow, clenched fist.
It's not a flailing arm though - he deliberately went for the man with his arm, and hit him in the face, long after the ball had gone. It'll be seen as dangerous play, can't be anything else.