[present / past] + とき, ~

[WhiteDay]

Hello there!

I'm learning about "とき" [when...] and would like to recheck if I got it right, because the use of it causes a little bit of confusion to me.

1. うちをでるとき、電気をけしませんでした.
When leaving the house, I didn't turn off the lights.

2. うちをでたとき、電気をけしませんでした.
When left the house, I didn't turn off the lights.

From above, 1. is the only correct one because one can only turn off the lights when leaving the house, not when they've left the house already. While 2. means after leaving the house, so it is not possible to turn off the lights then.

This is what I understand. Is it correct?

どうもありがとうございます
WhiteDay