I suppose it all depends on what you mean by 'simply', but yes, it is possible. As far as I know, you must export from Musescore as a musicXML file, then convert to lilypond.
I've done it with success, but not always 100% success. Use the program musicxml2ly, which comes with lilypond.
Or, if the phrase 'command-line' strikes fear into your heart, have a look here:
To participate in the discussions on Catholic church music, sign in or register as a forum member, The forum is a project of the Church Music Association of America.