Hi: & Welcome to LQ.
Looking here:
http://www.lakka.tv/
You should be able to install Zorin OS alongside of Lakka.
Any time that you want to dual boot with another os you will have to either shrink the partition of Lakka or tell the installer during the Zorin install that you want to install Zorin along side of Lakka.
OR you can manually partition your partitions during your install.
Once Zorin is installed Grub should take over and you should be given the choice of which os you want to boot.
Upon your fresh installation and your first boot into Zorin make sure that you update grub so it will find Lakka.
To look at the Lakka partition you can use the Zorin OS DVD and run sudo fdisk -l (small letter L) or you can use gparted Live.
Good Luck-