while the sun was shining, I set out on my walk. (use when)...... I have to write only one sentence, which one is better?

××(when the sun shone, I set out on my walk)
××(The sun was shining when I set out on my walk )
××(when the sun shone, I was sitting out on my walk)....
if there is another sentence please tell me it's an open answer questions. ​