We present an expression, based on scaled particle theory,for the calculation of cavitation free energy of molecules dissolved in nematic liquid crystals. This expression, depending on the orientation of the Solute with respect to the director of the mesophase, completes the procedure, recently developed, for the calculation of electrostatic free energy in such systems, and allows the quantitative study of the orienting forces in anisotropic solutions. We report some applications to small rodlike molecules dissolved in a liquid crystal, for which the free energy orientational profile and the relevant elements of the Saupe matrix are calculated using ab initio HF 6-31G** methods.