Re: Still looking for an electronic lock...
I just need a lock that is locked when power is off,
Apartment buildings tend to have this; the simplest one is an electromagnet pulling on the day latch of what is apparently called a rim lock: a door lock that sits exposed on the inside of the front door. The loop on the handle of the lock in the picture is exactly for such a magnet.
You may want to add a switch sensing if the door is properly closed, and a mechanism to close the door if it isn't.