You have to do the storyline up to where you liberate the frostwolf up northwest of your garrison, bladespire maybe?
I forget specifics but it's only a few quests. Drek'thar sends you to worgol, you go with Durotan to kill some stuff, you go across the bridge to the citadel there, yada yada yada... when you finish that part and can get the flightpath there (he'll offer you a quest to go back to worgol, Save wolf home i think - you can decline it) then you will be able to get the Grondo quest... it just pops up once you attack grondo now.
But the point was, just do the next part of the story. Maybe 15 mins and it's unlocked.
Mebbe get lucky too: