Will find-my-mac work if I have a password lock on my home screen? (Laptop was stolen and hasn't connected)

My daughter's laptop was stolen last Thursday night from her dorm room and hasn't come online yet. She had it set to require a password everytime it was used, so I'm wondering if that will prevent the thief from actually being able to connect the device to the internet. My guess is that to be able to use the laptop, the OS will have to be refreshed (command+r on boot) ... if this is the case, will it still be attached to our iCloud?