is stenge the same as lukke?
No. 'stenge' means to close for a longer period/permanently or to make inaccessible. 'lukke' means to 'close/shut'.
"Butikken stenger klokka seks" = "The shop closes at six"
"Skredet stengte veien" = "The avalanche blocked the road"
So even in the context of closing windows, the meaning is different?
There would probably never be a situation where you would "stenge et vindu", so they don't really convey the same meaning.
Is 'lukke' even taught in this course?