  We present a relativistic formulation of pion loop corrections to the
coupling of photons with nucleons on the light-front. Vertex and wave function
renormalization constants are computed to lowest order in the pion field,
including their nonanalytic behavior in the chiral limit, and studied
numerically as a function of the ultraviolet cutoff. Particular care is taken
to explicitly verify gauge invariance and Ward-Takahashi identity constraints
to all orders in the m_pi expansion. The results are used to compute the chiral
corrections to matrix elements of local operators, related to moments of
deep-inelastic structure functions. Finally, comparisons of results for
pseudovector and pseudoscalar coupling allows the resolution of a long-standing
puzzle in the computation of pion cloud corrections to structure function
moments.
