"Elsewhence" is a seldom-used word in the English language, and finding synonyms for it can be quite challenging. However, some alternatives can convey similar meanings. "Elsewhere" is a commonly used synonym that refers to a different place or location. "From other sources" can also capture a similar meaning to "elsewhence", emphasizing the origin or derivation of something. Additionally, "from alternative origins" or "from different beginnings" can be used to imply obtaining something from a different source. While these synonyms may not precisely encapsulate the rare usage of "elsewhence", they can help convey a similar sense of deriving from a distinct place or source.