  We present an analytically solvable model for correlated electrons, which is
able to capture the major Fermi surface modifications occurring in both hole-
and electron-doped cuprates as a function of doping. The proposed Hamiltonian
qualitatively reproduces the results of numerically demanding many-body
calculations, here obtained using the dynamical vertex approximation. Our
analytical theory provides a transparent description of a precise mechanism,
capable to drive the formation of disconnected segments along the Fermi surface
(the highly debated "Fermi arcs") as well as of the opening of a pseudogap at
hole- and electron-doping. This occurs through a specific mechanism: The
electronic states on the Fermi arcs remain intact, while the Fermi surface part
where the gap opens transforms into a Luttinger arc.
