We investigate the correlation between the bulge effective radius (re ) and disk scale length (rd ) in the near-infrared K band for lenticular galaxies in the field and in clusters. We find markedly different relations between the two parameters as a function of luminosity. Lenticulars with total absolute magnitude fainter than MT =-24.5 show a positive correlation, in line with predictions of secular formation processes for the pseudobulges of late-type disk galaxies. But brighter lenticulars with MT <-24.5 show an anticorrelation, indicating that they formed through a different mechanism. The available data are insufficient to reliably determine the effect of galaxy environment on these correlations.