In OTL, King John of England died of dysentery in 1216. Here he doesn't (because he doesn't come into contact with it). So Louis has more time to consolidate his rule, gain real allies, try to capture Dover, get papal approval, try to catch John, try to capture Dover, impress his dad (Phillip II), get crowned, try to capture Dover and so on. Could he hold England long enough to be crowned? Would he be disinherited from France? Would the Pope still excommunicate him? Did that already happen?
If he gets past those obstacles (Dover in particular according to Phillip II), could his successors hold onto England? Or would there be something similar to OTL's war of Scottish independence?