Elsie has the particular warmth of names that belong to no specific decade — it's old enough to feel classic, soft enough to feel sweet, and short enough that it doesn't burden a dog or cat with more name than personality. Female pets named Elsie tend to be described by their owners in gentle, affectionate terms, which probably reflects something about the name's selection effect as much as the animals themselves.
The Vintage Revival Wave
Elsie is part of the same naming wave that brought back Hazel, Mabel, and Pearl — names that skipped a generation of popularity and arrived back feeling genuinely fresh rather than retro-forced. In pet naming this manifests about five years behind human naming trends, which puts Elsie in the current sweet spot of adoptability. Golden Retrievers and Cocker Spaniels show up most often in this name's company.
Human Parallel
The human name Elsie has been climbing back into use as a given name — which means pets named Elsie will increasingly share the name with actual children. That crossover isn't necessarily a problem, but Worth flagging if you prefer names that feel exclusively pet-appropriate.
Sound Profile
Two syllables, "S" cluster in the middle, open "-ee" ending. It has a clear, pleasant phonetic finish that carries well and doesn't get swallowed in a noisy room. Easy to say affectionately, which matters more than most owners admit when choosing a name they'll repeat several thousand times.