The cylinder does need to turn to remove the lock cylinder. You can usually get the cylinder freed up by spraying wd40 into the lock cylinder, insert the key and tap on the end of the key with a hammer. The upper cover does not come off until the lock cylinder is removed. There is a hole in the top of the housing for the lock.
Make sure battery is disconnected, turn key to start and use a bent tip pick to depress lock inside hole, release key to ON position, and pull lock cylinder from housing.
I don't know of any other tricks to get the key to turn, sometimes you have to do more than tap, sometimes it takes a good whack. If the cylinder will absolutely not turn, you will have to force the upper column cover off over the cylinder, then use the new cylinder to figure out approximately where the lock aligns on the housing with the key in the off position. Drill a 1/8" hole at that location and use a pick through that hole to force the lock down so the cylinder can be removed.