PvP is not a Lava Burst Build.
Yes, you cast it on procs only but that’s it. If you take Volcanic Surge, and you should, you need not cast at all.
You should should spec out of Ascendant, Pwave, and passive buffs to Lava burst in favor of other things.
Volcanic surge is Brutal in PvP. Flat 30% increase damage to lightning, which you should easily be able to cast 3x instantly at the start of arena, or save for an alpha strike later.
Also, every PvP spec of Shaman should be casting 2x Counterstrike Totem (use Totemic Recall to get 2 out) period, end stop.
Yes, I know that both Volcanic Surge and Counterstrike Totem may be removed or nerfed in a few months when the patch goes live. But for the time being, your biggest PvP issue is that you are specced entirely wrong for PvP.
You should drop Farseer entirely, so that you don’t need to think about PWave or your 3 lava burst charges, and just go Stormbringer. Yes, we can acklowledge that Lava Burst sucks right now, so why are you basing your build around it in PvP?
You want to force yourself to have a bad time then continue with Farseer and accept the state of Lava Burst.
Stormbringer is all frontloaded, your setup is 2 elementals, 3x instant cast lightning bolt, and 2x Counterstrike Totem at onset of PvP. At this point, you should either be in control of the match, or outright killed at least one opponent. I don’t even take Hex.
If their any good, you may have to flex with your survivability. As in maintain Earth Shield, Stone Bulwark Totem, PvP Trinket, ghost wolf always, Gust of Wind (our version of Blink), etc.
I find out that most Posters like you die without ever having used Astral Shift.