Active modulation of the surface charge of a Lorentz spacecraft enables many capabilities-including inclination change, J(2) mitigation, and planetary escape without propellant cost. We develop Lagrange's planetary equations with the Lorentz force and use these analytical expressions to explore the dynamics. Behavior discovered empirically in earlier studies follows directly from the planetary equations. For example, the small tilt of a magnetic dipole has a negligible effect on the orbit. We present a closed-form expression that constrains the set of equatorial orbits for which planetary escape is feasible, and identify a sufficient condition for escapability from inclined orbits.