Just because you can't get to recovery does not necessarily mean you lost root access. They are not one and the same. LGs are kind of finicky about recovery, If the built in reboot to recovery option from the Power menu is not working, you can try an app like QuickBoot or via adb commands from the computer, or via the hardware buttons like so: http://itechtriad.com/articles/2014/...e#.U14kH_ldWSo
If you actually have lost your recovery (which is unlikely because CM would not change that), and still have root access when booted up with CM - you should - then grab Flashify from the Play Store, put your favorite recovery img file on your storage of the phone, and use Flashify to install the recovery for you. Very easy.