Hi: My lid switch is acting up. My laptop now turns on from sleep mode when I'm carrying it in my bag. The control for what happens with lid opening used to be in the Settings -> Power Management, but no more. Where has it gotten to? How can I stop automatic startup with lid open besides putting it in hibernation?

KDE has no control over when your system decides to wake from sleep - that is controlled by the BIOS or EFI firmware of your system.
I would suggest checking it to see if it has an option to only wake when keys are explicitly pressed.