Larson-Green, a corporate VP in Windows, is taking over for Windows President Steven Sinofsky, who has left the company.
Elop's return will see him take over Devices and Studios from Julie Larson-Green who will head to Applications and Services.
Julie Larson-Green to become leader of My Life & Work team, which is part of the company's Applications and Services Group.
Brian Cooley interviews Microsoft's Julie Larson-Green on sensors, services, and new ways of computing and design.
The president of Skype, Tony Bates, would handle acquisitions and relationships with developers, while Windows chief Julie Larson-Green would oversee hardware engineering for the whole company, says Bloomberg.
Julie Larson-Green, corporate vice president of Windows, says the company is having "meaningful discussions" about bringing older features of Microsoft's operating system to Windows 8.
New Windows chief Julie Larson-Green explains why the company felt the need to rethink the basic interface of its popular operating system.