Georg Andreas Sorge (1703-1778) was an organist, composer, and, most notably, theorist. His references to Johann Sebastian Bach show that they were friends.
I only knew his well-known trio's. But luckily Auke Jongbloed (user ajongbloed) made some nice editions of his chorale preludes. I'm surprised that we don't hear this music more often, since these are high quality organ works.
Check:
http://partitura.org/index.php/sorge-georg-andreas/
Sorge uses a trio form to accompany the cantus firmus.
I admit that I got a bit overenthusiastic with the added ornaments after line 2. I always make them up on the spot and let it mostly depend on the moment.
The score (thanks to Auke):
http://partitura.org/index.php/georg-andreas-sorge-jesus-meine-zuversicht/