Minion is right, but not quite for the reason presented.
Lacking Sleep 'completed' first, in a previous phase/turn, and therefore (by the rulings we have been given) the trigger there activates first (we have been told that the card active longest wins when two cards activate at the same time). Angel's Sword did not activate until Michael was put into battle, while Lacking Sleep has been there since before the battle, the trigger just waiting for him to enter.