I am not very familar with Lenel S2 myself, but I do not believe they have an OOTB connector / integration with SailPoint ISC. However, depending on the specific Lenel platform they do expose some SOAP or REST api’s where you may be able to use the OOTB SailPoint Web Services connector with some medium configuration. It may also be possible to integrate with the SailPoint JDBC connector directly at the database level, but I recommend the WebServices connector if your platform has the APIs.