Is it, then, regret for buried time That keenlier in sweet April wakes, And meets the year, and gives and takes The colours of the crescent prime?
Not all: the songs, the stirring air, The life re-orient out of dust Cry thro' the sense to hearten trust In that which made the world so fair.
Not all regret: the face will shine Upon me, while I muse alone; And that dear voice, I once have known, Still speak to me of me and mine:
Yet less of sorrow lives in me For days of happy commune dead; Less yearning for the friendship fled, Than some strong bond which is to be.
The regret that is awakening in Tennyson's breast might be the regret that he has wasted some time in his grief.
But it's not all regret. He recognizes that Arthur's face will still beam down upon him, and his voice is still speaking to him—figuratively speaking.
He's getting ready for a new bond and is feeling less pain from "the friendship fled."
Yay—Tennyson has really rounded a corner and seems to have worked through the worst of his grief. He's not only okay with being sociable, he's even preparing himself to have another bond that might be as strong as the one he shared with Arthur.