The first thing to note is that Dark Elves... are elves. What does this mean? It means that they are Toughness 3, and rely on their superiority in Weapon Skill, Ballistic Skill, etc. to defeat the foe. Dark Elves in particular are good users of magic, and can pack a punch in the Shooting phase if used correctly.
The Lore you choose to use depends on the rest of your army, and how you plan to defeat them. For example, if you wanted to use your Saurus to beat them up in combat, then consider taking Life or Light, and using your Skinks to provide shooting support. The only real weakness of Saurus is their low WS and I in comparison to Dark Elves.
I think you should take Life or Light. Fire is just magic artillery, which you won't need if you bring a couple of Salamanders to the table. Death, in my opinion, is perhaps a little short ranged. Your Skink priests will have Heavens anyway.
However, regardless of the Lore you choose, you MUST take at least two units of salamanders. Why? Because elves so do not like a str. 3, -3 save flame landing on their troops - they're all t3!
Also, ensure you have good magical defence... especially against spells such a Pit or Purple Sun.