A lanyard is to prevent loss of the blade. Think of sailors working in rigging on old stick and cloth vessels. Or riggers working on cranes, scafolds, or hoisting gear.
If you can pick up your knife after dropping it, and not drop it on someone if you let it go, then you likely don't need a true lanyard.
And positioning of a lanyard, is a matter of pure personal preference, they can be made for neck wear, belt wear, wrist loop whatever accomplishes the goal of a lanyard's job. Typical examples are belt worn, or neck-tied.