From the report of BBC, there are one sentence that make me attention:
United's statement announcing Solskjaer's arrival as caretaker manager made no mention of whether or not he will return to Molde when the Premier League season ends.
But the Norwegian club stressed they were only "lending" Solskjaer to United, indicating they expect him to return to his previous role.
There are a lot of cases of borrowing a player from other clubs, but seems this is the first time I hear a club borrow a manager from other club.