ΔE 41.5, loose: different enough that you should pick on purpose. Yellow Green is noticeably lighter, much more saturated, warmer than Elven Green.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 41). Yellow Green is noticeably lighter, much more saturated, warmer than Elven Green.
The same difference applies the other way round: Elven Green is noticeably darker, much more muted, cooler.
ΔE is the colour difference between our two swatch estimates: under about 6 is close, over about 15 is loose. Real paints also differ in finish, coverage and how they thin, so test before you commit.
See Elven Green on the colour wheel See Yellow Green on the colour wheel
All matches: Elven Green equivalents · Yellow Green equivalents