These matrices are defined in 'lav_representation_lisrel.R' in the unzipped package source file.
Seems 'nu' is the intercept for latent variables,
'beta' is the coefficients for structural model
and 'lambda' is the coefficients for the measurement model.
I still want to know the meaning of the extra matrices,
'tau'
'alpha'
'delta'
When will these matrices show up in the model?