  We study the effects of gravitational lensing on the estimation of
non-Gaussianity from the bispectrum of the cosmic microwave background (CMB)
temperature anisotropies. We find that the effect of lensing on the bispectrum
may qualitatively be described as a smoothing of the acoustic features
analogous to the temperature power spectrum. In contrast to previous results,
for a Planck-like experiment which is cosmic-variance limited to L=2000, we
find that lensing causes no significant degradation of our ability to constrain
the non-Gaussianity amplitude fNL for both local and equilateral
configurations, provided that the biases due to the cross correlation between
the lensing potential and the integrated-Sachs-Wolfe (ISW) contribution to the
CMB temperature are adequately understood. With numerical simulations, we also
verify that low-order Taylor approximations to the lensed bispectrum and
ISW-lensing biases are accurate.
