Just to confirm this as I have checked on a simulator. The aircraft will change the localizer dagger on the PFD to the front course loaded into the MCDU (so long as this is changed before the MCDU data lock at 700AGL, anything below 700AGL has no change).
The aircraft will continue to track the localizer like normal showing the lozenge central on the PFD (still tracking the correct localizer beam) but the dagger will be whatever is loaded in the MCDU. Then in the flare the aircraft will align with the course entered into the MCDU. The 5 degree limit (before go around is required) between ILS course and course on the PFD is mentioned elsewhere in the FCTM where in a crosswind you can land with up to 5 degrees of drift. Anything greater than this then you may risk damage to the gear due to torsional forces.