  The large $N_c$ limit provides relations that can be used to calculate the
$\gamma^\ast N \to \Delta(1232)$ quadrupole form factors at low and
intermediate $Q^2$ under the assumption of the pion cloud dominance. There are
two limitations in those parametrizations. First, the parametrization of the
Coulomb quadrupole form factor underestimate the low $Q^2$ data. Second, when
extrapolated for the timelike region, the form factors violate Siegert's
theorem by terms of the order $1/N_c^2$. We propose here corrections to the
parametrization of the electric quadrupole form factor, which violate Siegert's
theorem only by terms of the order $1/N_c^4$. Combining the improved large
$N_c$ pion cloud parametrizations with the valence quark contributions based on
a covariant quark model for the quadrupole transition form factors, we obtain
an extrapolation to the timelike region consistent with Siegert's theorem, and
accomplish also a very good description of the data.
