I'm under the impression that magical arm shield makes your monster into the attack target, unlike a very similar card called confusion chaff. Since the card is the attack target, skyscraper would still work.
What I would get this from is the words "it is attacked instead", which implies that the monster is actually attacked, making it the attack target. Confusion chaff has the words "conduct battle between", and has no mention of attack, which would be the difference in wording that shows whether these kind of cards create a new attack target or not.
So yeah, skyscraper would work.