This paper assesses the efficiency of the "Language Immersion e-Course" developed at the London School of Economics and Political Science (LSE) Language Centre. The new self-study revision e-course, promoting students' proficiency in spoken and aural Russian through autonomous learning, is based on the Michel Thomas method, and is focused primarily on lexical work, which students commonly consider to be one of the biggest challenges in language studies. The course, targeted at the intermediate (A2/B1) level of proficiency in Russian (with a specific focus on language for Social Sciences) was incorporated into students' guided revision programme. The package is downloadable as a mobile application offering more flexibility for the users. This paper focuses on the pedagogical evaluation of the project (through students' feedback and their exam performance), and analyses the learning implications of such e-courses as a valuable alternative and added value to classroom teaching. Given that lexical command plays a fundamental role both in fluent language production (speaking and writing) and efficient comprehension (listening and reading), the paper asserts the benefits of such e-courses for blended learning programmes, as well as for improving overall efficiency of students' second language acquisition. [For the complete volume of short papers, see ED572005.]