Empty File Start-up

Yes, it’s sometimes convenient to have the previous file open when Scrivener is started.

But wouldn’t it be nice to have the choice? A setting in preferences (a checkbox) labeled: Open Last Edited

And below that, a fill-in box/Choose button combo for setting the default user-defined template file.

In Scrivener for Windows, I think the following checkbox is what you are looking for…
Tools > Options > General > Reopen projects that were open on quit

It should be similar in Scrivener for Macintosh OS X.