The "li" means "my". (It's the same element as Liat, Lior, Liron, for example.)
There's a Hebrew name/word Mor, a name of a plant (myrrh in English). That's probably the "mor" element, although the meaning as a whole feels a bit odd to me. "My myrrh" doesn't quite fit in with "my light", "my song", "you're mine", etc.