I read it as ›sfork‹.

In my humble opinion, the linking part (name?) is either too thin on the S or too wide on the t (in other words : either linking too much on one side, not enough on the other). Have a look at Parisine plus for a good example of how to solve that problem - there might even be a Parisine Plus Italique/Italic.

I think this logo would be far stronger without the ligature. It's a bit forced and unnecessary and Caecilia has enough interest on its own without the modification. My compliments on your typeface choice. Just keep it simple and concentrate on the symbol/imagery surrounding the logotype.