"I called Herschel. He's a fantastic librettist and a fine composer," Mr. Cohen said in a telephone interview from his home in Upper Montclair, N.J.  Herschel Garfein, who often collaborates with Mr. Cohen, wrote the libretto for the opera "Elmer Gantry," which garnered a Grammy this year for best contemporary classical composition. Mr. Garfein suggested that members of the Susquehanna Valley Chorale post stories about Alzheimer's patients they knew on a blog that was part of the choir's website.