First of all note that writing is different than reading.

1. The Roman alphabet is not completely appropriate for Sanskrit. Please remember to consider signs including an aspirate (like kh-, gh-, ch-, jh-) or representing a diphthong (like ai or au) as INSEPARABLE. E.g. ai-śva-ryau and not *a-i-śva-rya-u
2. the Devanāgarī (short for all other Brahmī-based Indian scripts) writing system has its own conventions, which do not apply outside it. Thus, refer to syllables, not to Devanāgarī graphemes. E.g., dhar-ma-tat-tva and  not *dha-rma-ta-ttva
3. You do not know what is an admissable syllable in Sanskrit (syllables are not entirely “objective” entities and they vary a lot from language to language, although all languages agree in needing a vowel-sound in each syllable, see the figure for a glance into the different English syllables) and you do not want to dwell into Prātiśākhya discussions about it (or to read Giovanni Ciotti’s article here)? Use this very simple rule of thumb: A syllable is one with which a word can start. Thus, tva– is an admissible Sanskrit syllable, whereas *-rva is not.
4. Thus, only leave a consonant with the preceding vowel if it cannot go with the following one. E.g., Ma-dhva instead of *Madh-va, because there are words beginning with dhv+V[owel], e.g., dhvaja. Similarly, Pañ-ca-rā-tra instead of *Pa-ñca-rāt-ra.

Which criteria do you apply?