Complex sentence: Sometimes the letters representing these words are written in lower case, such as in the cases of TfL (Transport for London) and LotR (Lord of the Rings); this usually occurs when the acronym represents a multi-word proper noun.
Split into simpler sentences: Sometimes the letters representing these words are written in lower case, such as in the cases of TfL (Transport for London) and LotR (Lord of the Rings). This usually occurs when the acronym represents a multi-word proper noun.