Immerse your Tempered Quel'Delar in the Sunwell. Speak to a Warden of the Sunwell when you are ready to enter the Sunwell Plateau.
I admit, I was skeptical that you had actually re-forged Quel'Delar and I did not expect Thalorien's spirit to reveal itself to you. You cannot understand what it means to me and to the rest of my people that Quel'Delar has been recovered.
As promised, I will admit you to the Sunwell and you will find the leaders of Silvermoon within. Carry the sword to the chamber of the Sunwell and immerse it. The blade will bond to you. When that happens, carry it to Caladis Brightspear at Quel'Delar's Rest.
This is unbelievable, <name>. You've really done it! All of the quel'dorei have heard of Thalorien Dawnseeker and Quel'Delar, but no one ever thought the sword would be restored.