ΔE 23.3, loose: different enough that you should pick on purpose. Phoenician Purple is noticeably darker, cooler than Elder Flower.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 23). Phoenician Purple is noticeably darker, cooler than Elder Flower.
The same difference applies the other way round: Elder Flower is noticeably lighter, warmer.
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 Elder Flower on the colour wheel See Phoenician Purple on the colour wheel
All matches: Elder Flower equivalents · Phoenician Purple equivalents