ΔE 34.5, loose: different enough that you should pick on purpose. Sapphire Blue is a little lighter, much more muted, cooler than Elven Armour.
Not as a straight swap; see the closer alternatives below. Loose match (ΔE 34). Sapphire Blue is a little lighter, much more muted, cooler than Elven Armour.
The same difference applies the other way round: Elven Armour is a little darker, much more saturated, 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 Elven Armour on the colour wheel See Sapphire Blue on the colour wheel
All matches: Elven Armour equivalents · Sapphire Blue equivalents