Will Lion download from Mac App Store resume if network connection interrupted? I'm contemplating downloading it but I'm in an area prone to connectivity outages. Or does it install a pre-loader which then downloads the actual disk image (which I can curl)?
App applications downloaded from the App Store will automatically resume if your network service is interrupted. The Lion download is a DVD sized .dmg file that contains the OS, not a pre-loader.

If your download does get interrupted you can control + click on the Lion icon in your dock then click resume.