The Giant of the Generation

Not The Godol Hador has shut down his blog. Since he has removed all the material I found objectionable, I'll finally give him a link.

Let me take this opportunity to raise a question that has been bothering me for a while. Grammatically, shouldn't it be "Gedol Ha-Dor" and not "Gadol Ha-Dor"? Please enlighten me in the comments if I am wrong on this.