Somewhat.
Elemental Damage only affects the weapon its on.
So lets say you are duel wielding a
Blade of the Silenced (14/24 + 1 poison) and a
Mace of Warped Brutality (20/26 + 1 poison). Total you have +2 poison damage, but each weapon only counts its own poison damage on itself. Thus the Blade is 15/24 and the Mace is 21/26 when the poison damage isn't resisted. But if you cast a poison spell, it would gain the +2 benefit from both weapons.
Now to hopefully dismiss some long standing misunderstandings concerning elemental damage and weapons, lets take the
Scimitar of Chaotic Flame as the +3 fire will give easier to understand numbers. Numbers used are confirmed, and parsed a long time ago by Zaela.
Elemental damage is all or nothing on weapons. So on every swing, the Scimitar will either be 14/20 or 17/20 depending on if it makes the resist check. What does that mean for weapon comparisons?
An enemy with a FR of
100, would get the 17/20 about
66% of the time and the 14/20
33%.
Or if looked at from a slightly different angle,
66% of the time you'd get the full +3 fire damage.
33% of the time you'd get +0 fire damage.
Thus, on average, the +
3 fire damage is worth
1.98 damage on the 100 FR mob (66% of 3).
While +3 fire dmg isn't literally turned into 1.98, you can short hand your expected damage of the Scimitar to 15.98/20. Thus over a reasonable period of time, the Scimitar and a 16/20 weapon would do fairly equivalent damage on a 100 FR mob.
The next relevant question is, how common is it for a mob to have more or less than 100 resist? Outside of raids, unless the mob is immune, you are looking at less than, most all the time. In raids it starts out notably higher, but depending on the resist can be debuffed in short order to ALOT lower. Assuming your raid isn't lazy, you are generally doing more damage with an elemental weapon in a raid, then with an elemental weapon in a group or solo.
There are a few other factors I'm not mentioning here, and I won't give you some crazy table showing odds of resist per resist level at a 5 level range either way (we do have that by the way). But I've said it once, and I'll say it again, +elemental damage on weapons is highly under-rated by the community.
EDIT:
Silly me I forgot the very reason I started typing all that out. Worn Elemental Damage does
NOT affect anything weapon related
EXCEPT monk and bst fists. So wearing +2 poison gloves wouldn't help your Mace of Brutality, but WOULD help you punching something or casting poison related spells.