For more info see http://stackoverflow.com/q/21155307/485115.
Until the issue is resolved I see the following workarounds:
Change the appropriate timeout settings in the config of the db, so that they are higher then the defaults expected by C3P0 (SORM currently doesn't change any of those properties).
Set the C3P0 properties in the appropriate ".properties" file. For more info on that you can consult the C3P0 documentation.
Introduce connection timeout setting (#37)
0.3.13-SNAPSHOT introduces a timeout parameter for Instance.