If you watch Marcos Tinocco's Lasso Guard DVD, you realize he never plays that De La Riva hook stuff with other leg, because it's easy to counter. Either play De La Riva, or Lasso, not both at the same time. You can switch between, but you have to let go of the other.
This is why you don't generally use de la riva hook with lasso. You control the hip(Source: Marcus Tinocco Lasso DVD). And even if they somehow manage to pass your leg, you frame against his hand and restore guard. You never, ever let them grab your head.
