  The next generation of CMB experiments should get a better handle on
cosmological parameters by mapping the weak lensing deflection field, which is
separable from primary anisotropies thanks to the non-Gaussianity induced by
lensing. However, the generation of perturbations in the Early Universe also
produces a level of non-Gaussianity which is known to be small, but can
contribute to the anisotropy trispectrum at the same level as lensing. In this
work, we study whether the primordial non-Gaussianity can mask the lensing
statistics. We concentrate only on the ``temperature quadratic estimator'' of
lensing, which will be nearly optimal for the Planck satellite, and work in the
flat-sky approximation. We find that primordial non-Gaussianity contaminates
the deflection field estimator by roughly (0.1 f_NL)% at large angular scales,
which represents at most a 10% contribution, not sufficient to threaten lensing
extraction, but enough to be taken into account.
