Good afternoon, could someone please clarify for me where the option in Group Policy is on a 2012k server for Windows 8 users to be able to lock their session?

I need them to be able to either go to start, click on their username and for lock to be in the drop down next to change account picture and sign out or I need it to be there on CTRL+ALT+DEL.

At the moment, our windows 8 client systems only show lock for an administrator user.
I found this image on another site, ignore the arrows, it shows the 'Lock' drop down option I am referring to:
Hope that makes sense.