As Digital Engineering employs a digital thread with a broad range of interconnected models, it can be difficult to govern linked models across disciplines and contractual boundaries. After an introduction to the challenges of model governance, a survey of related literature is provided. An Elastic Model Governance Guide for the digital thread is then described. Key features include: (1) model-based guidance with in-model work instructions; (2) integration of the overall Model Governance System, Digital Engineering Environment infrastructure, individual models, and composite models; (3) scoping of model purpose and resolution of technical debt; (4) automated validation for insight on compliance; (5) customization for flexibility and tailoring. Excerpts from the governance guide are provided and discussed, and next steps are given. Integrating model governance practices with additional mechanisms for flexibility, scalability, and automated validation provides robust control over the Digital Engineering ecosystem to enhance the value delivered to customers.