Two years later the whole family moved after her to Kristiania, enrolling in theology studies at the Royal Frederick University.
The profession as clergyman was not available for women at the time, but Lerche as active in Christian organizational work.
She was behind several social establishments such as orphanages, recreational homes and housing for homeless people.
She also visited women's organizations, hospitals and Sunday schools to spread the Christian word.
Together with secretary in the Kristiania Inner Mission, Carsten Hansteen, she also conducted exegetic studies of the Bible.