Any time in the past, from 1 second to millions of years previous.
Daddy didn't we walk the dog lastertime?
Did the Egyptians build that pyramid lastertime?
Lastertime- (n.) a non-specific referrence to the last time something happened or the last time you or a group of people did something in the recent past. syn. see Yestertime (etymology: North America, yr. 2000- Allegra Davis a small child invented the word from yesterday, last-time and yesteryear mix)
"Remember, lastertime you told me I could ride on the tractor with you."
"You said lastertime that I could get a toy when we came back here"
"Lastertime I updated my resume, I think I added that."