Magnetostriction measurements have been performed on single-crystalline samples of Ce1-xLaxRu2Si2 in magnetic fields up to 8.5 T. The data are discussed within a simple scaling model, and provide further support for the existence of a single energy parameter in the heavy-fermion state (x&le0.05). The samples were cleaved from single crystals grown by the Czochralski technique, to yield plan parallel surfaces perpendicular to the tetragonal axis. They were mounted in a capacitance cell that was also used for experiments on pure CeRu2Si2.