Have you already procured the actual marriage document to see whether it contains any additional information about Delphine Marcow? (That could be either a maiden surname or a surname from a previous marriage.)
Have you procured William YARRINGTON's obituary, death certificate, or will/probate files? They may give further information about Delphine.
as you may already know, William's son was in the newspaper business in La Crosse for many years. It's possible the La Crosse library has further information about the family in some sort of surname file. I'm not familiar with their holdings, but it may be worth a query by mail or phone.
There were other "MARCOWs" in La Crosse County in the 1880s:
Marcow, Mary, married Martelle, Amand on Jul 03 1883 in La Crosse Co.
Marcow, Leopold O, was born Sep 09 1889, in La Crosse Co.
Also note that many variant spellings appear on La Crosse County documents for this general era: