emerillon does not handle command line arguments as of version 0.1.0 at all (and from the news messages, didn't learn it since then).

at least --help and --version should be implemented as they are fairly standard.

furthermore, i suggest to add a way to start emerillon at a position on the map. possibilities include

--placemark=NAME -- look up a placemark name
--lat=LAT, --long=LONG -- open at given coordinates
--zoom=ZOOM -- i'm not sure what is a card source independent way to specify zoom levels
--url=URL -- parse common urls that describe places; suggestions include

* the urls that can be exported to clipboard using the plugin
* geo: urls as defined at [1] (it's not an accepted standard, but implementing it won't hurt)
* the urls from [2]

[1] http://ietfreport.isoc.org/all-ids/draft-mayrhofer-geopriv-geo-uri-01.txt
[2] http://placetime.com/geopoint/wgs84/