Elisions not performed correctly by latin HexameterScanner and VerseScanner

[bblumenfelder]

Describe the bug
In two cases elisions are not performed correctly:

1. Whenever em at the end of the word meets a vowel in the next word.
2. Whenever an elision should take place, h at the beginning of a word is treated as ordinary consonant.

To Reproduce Bug 1
Steps to reproduce the behavior:

from cltk.prosody.lat.hexameter_scanner import HexameterScanner
hexameter_scanner = HexameterScanner()

verse1 = "quem quidem ego actutum (modo vos absistite) cogam"
print(hexameter_scanner.scan(verse1).working_line)
# Out:          quēm quidem eg  āctutūm  modo vos ābsīstite  cogam
# Should be:    quēm quid eg  āctutūm  modo vos ābsīstite  cogam

verse2 = "Qui potis est, inquis? Quod amantem iniuria talis"
print(hexameter_scanner.scan(verse2).working_line)
# Out:          Qui potis ēst  īnquīs  Quod amāntem īnjuria talis
# Should be:    Qui potis ēst  īnquīs  Quod amānt īnjuria talis

verse3 = "ille, datis vadibus qui rure extractus in urbem est"
print(hexameter_scanner.scan(verse3).working_line)
# Out:          īlle  datīs vadibūs qui rur  ēxtrāctus in ūrbem ēst
# Should be:    īlle  datīs vadibūs qui rur  ēxtrāctus in ūrb ēst

To Reproduce Bug 2

verse4 = "non potuisse, tuaque animam hanc effundere dextra"
print(hexameter_scanner.scan(verse4).working_line)
# Out:          nōn potuisse  tuaqu  animam hānc ēffūndere dēxtra
# Should be:    nōn potuisse  tuaqu  anim ānc ēffūndere dēxtra

verse5 = "perque hiemes aestusque et inaequalis autumnos"
print(hexameter_scanner.scan(verse5).working_line)
# Out:          pērque hiemes aestūsqu  et inaequalis autūmnos
# Should be:    pērqu iemes aestūsqu  et inaequalis autūmnos

verse6 = "monstrum horrendum, informe, ingens, cui lumen ademptum"
print(hexameter_scanner.scan(verse6).working_line)
# Out:          mōnstr   hōrrēnd    īnfōrm   īngēns  cui lumen adēmptum
# Should be:    mōnstr   ōrrēnd    īnfōrm   īngēns  cui lumen adēmptum

The same bugs occur with VerseScanner:

from cltk.prosody.lat.verse_scanner import VerseScanner
verse_scanner = VerseScanner()
print(verse_scanner.elide_all(verse1))
# Out:   quem quidem eg  actutum modo vos absistite cogam
print(verse_scanner.elide_all(verse2))
# Out:   Qui potis est inquis Quod amantem iniuria talis
print(verse_scanner.elide_all(verse3))
# Out:   ille datis vadibus qui rur  extractus in urbem est

Environment:

• CLTK 1.0.17 in different environments

Additional context
Elision rules are specified here (unfortunately in german) and here

[kylepjohnson]

@bblumenfelder thanks for opening this, and apologies that I did not reply sooner.

@todd-cook do you have an idea of the effort necessary to fix this? If it is too much, then let's think about a way to track this long-term.

Benedikt, if you would like to help out do some development work with us, please reach out. Even just finding bugs like this is very helpful.