Elemental damage and lightning damage nodes

Hey all,

I'm fairly new to PoE and I've been lurking around the forums quite a bit recently.

I've been browsing the passive skill tree and I plan to make a Lightning Arrow or Lightning Strike Marauder.

I have a question about the elemental damage nodes and lightning damage nodes. Will they work to increase LA or LS? The ones that say "increased elemental damage" and "increased lightning damage".

I find it odd that all the builds I see, people go into the Templar tree to get those elemental weapon damage nodes, but skip the elemental damage nodes right above it and the lightning damage nodes go ignored as well...

Linked build for reference.

http://www.pathofexile.com/passive-skill-tree/AAAAAgEBAnEEswthEtkUTRZvGS4ZhRo4G0UdFCSqJ-0pLjIJMn4yiTboNuk6UjrYOuE9_E3YTeNQUFRJVcZWBFfiWGNYr1nzXz9hUmaeZ71uqnKpd-V4DXloe4x8uHzZhmCHKYjxjHaMz46_j0aQVZuhn8uiAKZXp4SpbqxZrKquk7Xyud3AGsEExtjPZdDQ1I_fv-Nq51LsOO5v7w7wH_Iv8932SPrS_o8=

Perhaps I should just rephrase.

Will getting the elemental damage and lightning damage nodes enhance the DPS on lightning strike and/or arrow?

Any help would be greatly appreciated!