It should resume. However, I recommend being extra careful and downloading the video to a PC before starting the app by using iTunes File Sharing as described here:
http://support.apple.com/kb/HT4094TimeLapse should not crash! Any info you can provide (was this Classic or Express, what settings you used, was the session interrupted, how the session stopped) can help me fix the problem and ensure it does not happen in newer versions of TimeLapse.