Els works since 1985 at the interface of employment law and corporate law, with a focus on transaction work, transfer of undertaking, reorganisations, internal investigations, (European) employee participation, privacy and executive advice. She is a leading expert in the field of European and international employment law. 

In 1999 Els set up the world-wide employment law network within Landwell and PricewaterhouseCoopers, managing this network as Global Head of Employment until 1 January 2004. She is a regular author and speaker in the Netherlands and abroad on employment law. She teaches a variety of courses and takes part in several international think tanks on HR and international employment law.

Until recently Els chaired the Employment and Industrial Relations Law Committee of the International Bar Association (IBA) and the European Employment Lawyers Association (EELA). She is a council member of IBA’s Global Employment Institute and an active member of the American Bar Association (ABA) and of the regular Dutch associations of employment law. Els is on the Editorial Board of PLC Cross-Border Labour & Employee Benefits Handbooks and the Alumni Board of the Faculty of Law of Radboud University Nijmegen. Els is chair of the board of the Amsterdams Kleinkunst Festival.

Els comes recommended by leading legal directories including the Legal 500, Chambers Europe, European Legal Experts, Who’s Who Legal Management Labour & Employment, Global Counsel Handbook Labour and Employment Benefits and The Legal Media Group Guide to the World's Leading Labour and Employment Lawyers.