Subionospheric very low frequency (VLF) signal perturbations observed at multiple sites in association with individual lightning discharges exhibit onset delays which steadily increase with increasing L-value. The timing of the onsets and the inferred spatial extent (~1000 km) of the ionospheric disturbance are consistent with those expected for electron precipitation induced by obliquely propagating (i.e., nonducted) whistlers. ¿ 1999 American Geophysical Union