Do you have the quest "The Hand of Morkul" active? Possibly from already picking it up before you were told to go aid the Morkul clan?

If so, you need to go and complete that quest, and then go back to the Morkul stronghold after.

If not, and if talking to Lazghal doesn't work (is she the one who walks around close to the crafting stations in Morkul stronghold? If not, I think the quest is telling you to talk to the wrong person, because that's where I remember the quest giver for "The Hand of Morkul" being), try going to Morkul Descent - you should find Ashaka there, and I'll bet that you can get the quest from her.