Information for all Lx 4.2 users: If you have a fully updated system you should have the package bluez-5.55-5. If so bluetooth should be enabled already or enabled upon your next boot if the package was just installed.
If for some reason this is not the case open Konsole and run this command:
sudo systemctl enable bluetooth
If you encounter problems start a new thread with a descriptive title and information regarding your issue.