Well Stormcrown always does the same amount of damage and doesn't help your ratios. I personally don't think the build you propose is "efficient". The effectiveness of a build has to do with the player. I can copy a pros build, but that doesn't make me a pro.

The reason I wouldn't use the combo you propose is two-fold. First, Stormcrown is for camp clear primarily. That's why you are seeing a lot of the pro taka players doing things like Tension Bow + Stormcrown or Aftershock + Stormcrown. Tension bow and aftershock in them selves don't offer consistent camp clear, adding stormcrown allows the jungler to farm faster. However on lance a double Sorrowblade build, or a Tension Bow + Sorrowblade will be plenty powerful enough to clear your camps, plus remain effective on heroes.

The second reason is that the other half of Stormcrown, the stats, are about cooldown and energy. Well Lance doesn't use energy, and his cooldowns are already ridiculously low, so you aren't gaining from these statisitcal benefits either.

Sorrowblade and Tension Bow are the only two items you should bother with on Lance. A very common build is to see Lance as a jungle with double Sorrowblade. His WP ratio dropping is even more of a reason to use Sorrowblade